Tractor



P. E. HOLT.

TRACTOR.

APPLlcATloN FILED ocT.1,'1917.

4 SHEETS-SHEET I.

Patented Apr. 13, 1920.

MOU.

WANN

P. E. HOLT.

TRACTOR.

APPLICATION FILED ocT.l,1917.

Patented Apr. 13, 1920.

4 SHEETS-SHEET 3.

"I'H um E s s E N T .1 u

ww /W www..

P. E. HOLT.

TRACTOR.

APPLICATION FILED OCT-.1, i911. 1,336,961 Patented Apr. 13, 1920 4 SHEETS-SHEET 4.

To all 'whom t may concern Be it known that ll, Puur E. "ii-tom, a citizen ci the United States, residing at Stockton, in the county of San Jbaquin-'and State to adaptthe machine especially for use as' a gun mount for traveling over rough or broken terrene such as is encountered in the field ci war.

Tractors oi this type employ exceedingly long tracks ranging Jfrom eight to fourteen feet from center to center of the carrying wheels. With a rigid truck trame the track spans the ditch or depression, and its tractive surface is therefore limitedto the ends orp'the tracks', the intermediate portion of the track being at this time out of engagement with the ground. Also when embankments are encountered the iront end of the track, where a rigid truck frame is employed, is liable to dig its way into the earth and stall the machine.

ln the present invention ll hinge the truck frame intermediate its ends in suoli a way that it will be :tree to move downwardly away from the main frame oil the machine and enable the track to conform to the depressions in the ground, so that the maximum tractive surface of the machine will be maintained. Also the iront truck section, which carries a guide or idler wheel for the front portion ot the track, is so arranged that it will flex upwardly. when striking an embankment and prevent digging in of the iront portion of the track. rll`he angle which the front truck section is capable of assuming is such that the track will readily pass over emban'kments which are practically vertical.

One form which my invention may assume. is exempliiied in thefollowing description and illustrated in the` accompanying drawings, in which- Figure l shows a side elevation of a device embodying my invention.

Fig. 2 shows a plan view of the same.

Fig; 3 shows a diagram illustrating the the device.`

r.l `he machine, as here shown, comprises a 'main trame 10, oi suitable construction, supl specification or" Letters Patent. .PayitQmttll A1012 iig, l ippicltl @165. @Gtll 3:, 1917. SETI-12,1 2li). 194:,253.

position assumed by the truck sections inl passing over a depression or climbing an embankment.

F ig. *a shows a plan view of the pivotal connection tor the'iront truck.

Fig. 5 shows a modiied ormoi connection oi the rear truck to the chassis.

Fig. 6` shows a modiied construction of ported at its sides upon a pair 'of endless, flexible, self-laying track mechanisms. Each track mechanism includes a driving sprocket wheel 11 at the rear iiXed upon one end of a driving shaft i12, which shaft is journaled on the main -traine. A. hinged truck trame, consisting of front and rear sections 13 and 14, respectively, supports the weight of the main trame, andeach truck frame carries a series of flanged. rollers V15, the rear one being shown as havingsix and the iront one as having three. The rear section is in no way-connected to the rear driving sprocket wheel and is slidably and pivotally con.- nectedto the main "frame, as will presently appear. The iront section is pivoted intermediate its ends upon one end of a transi verse shaft 16- through the medium of a spring mounted bearing presently to be described; the said shaft 16 being hired to the main trame at the front thereof.

The front end of the front truck section projects beyond the front of the main hframe and receives an idler sprocketwheel 17 ata its forward end. An endless chain track 18 is carried by the front and rear sprocket wheels 11 and 17 andforms at its ground stretch a track upon which the flanged rollers 15 operate. rThe hinged connection between the front and rear truck sections is by means or" a stub shaft or pin 19, opposite trucks being not connected together transversely at this point. The construction is suchthat the truck frame members will move downwardly away from the mainframe at their joint 19 to a degree suiicient to insure the full tractive effect of the chain track in passing over, depressions, and the like, and .also to permit the front truck section to move upwardly in a vertical plane about its pivotal connection -with the main frame to an angle greater than 45o with respect to the plane of the rear section, so that embankments may be climbed without danger of the front portion of the track digging into the earth. A

lIn order to permit`this flexing of the truck sections, I connect the rear section slidably and pivotally with the main frame at a point near therear end of the said truck section. This may be done in any one of several improved ways, two such being illustrated herewith. In Fig. 5 this is accomplished' by supporting the main frame upon the rear truck section through a V-shaped block 20, carried on the end of a cross sill 21 and employing spaced clips 22 depending from said sill, one at each side of the truck frame to engage beneath flanges 23 on the latter. This connection not only permits pivotal and jslidable movement of the truck frame member relative to the main frame but it also prevents the said trucky away from the main frame cham sags.v v

from droppingwhen the trac In Fig. 1, Iy show a modified form of connection consisting of a 'flanged roller 24 journaled upon the main frame near the rear end thereof and resting upon the top of the rear truck frame member. This permits the desired pivotal and slidable movef ment and has the advantage of overcoming friction.l Except for the slidable andpivotal connection at the rear and the pivotal connection at the front, the hinged truck frame is free of the main frameand is capable of assuming almost any upwardly diverging angular position to suit the contour of the ground.

In order to vsecure the advantage vof a spring mounting for the main frame, I arrange a pair of helical compression springs 25 beneath each side of the main frame, forwardly of the slidable and pivotal connection ofthe rear truck section, said-springs,

when the truck section is in normal position, resting upon the top of. the latter and cushioning the main frame. These springs .are secured in place to the main frame and `disconnected from the truck frame so that the latter will be freeto move downwardly' as far as the position of the track will permit. Also the front end of the main frame is resiliently supported upon the front truck'` sections by means ofy a yielding bearing for the ends of the transverse shaft 16. This bearing comprises a block 26 receiving theI end of the shaft and having lfore and aft extending arms 27 resting upon the helical compression springs 28 seated on the truck` frame. An upwardly projecting member 29, on the truck frame, has a vertical slot 30,

' permitting relative movement vertically in employ-apush-rod 32, on each end of the driving shaft 12, extending forwardly and connected with the projecting end of the cross sill 21. Also a thrust member 33 is ad-4 justably secured to the member 29- at each side ofthe-machine andextends forwardly to the adjacent idler wheel 17, loeing'g'connected to the bearingsv 33a of the latter. Said bearings are adjustable back and forth upon the front frame member to change the position of the front idler Wheel, whereby to tension the track.y .Supports for the upper run of the chain track may be inl the form of a series of rollers 34 journaledv on supports fixed to the side of the main frame,4 while the track immediately behind the front idler wheel is supported upon aseparate roller 35 carried by the thrust -member 33 and being, therefore, movable with the front end ofthe truck.

A motor 36, located at any desired point on the main frame, operates the rear driving wheels l1 through the medium of suitable change speed transmission mechanism v37, whereby to propel the machine. A friction clutch 38 is interposed between lthe transmission and driving axle of each side and steeringis effected by varying the relative speeds of the two'tracks, brake-mechanism 39 being employed to hold one track stationary while the other is in operation.

"In operation, the truck sections will flex or sag as is desiredv to negotiate ditches, shell holes, and the like, and thereby thetrack will be kept in engagement with the ground throughout its full length. The hinged sections are capable of assuming any relative position varying from a straight line to an upwardly ldiverging angle of'approximately 135. In soflexing, however, the track will not have any appreciable amount of slack, since the rear driving wheel is held in fixed position and the slack caused by the movement of the front wheel toward the rear wheel will be taken up by the deflection of the truck frame members at the bottom of the track.- The front truck sections projecting as they do considerably forward-of their pivotal connections with the main frame, and, beingfree to turn on the shaftl, will tilt pwardly when meeting an embankment a'hd assume an inclination suliicient to perinit the track to climb a vertical rise without liability of digging into the earth.

-In certainlconditions of ground, as, for instance, where narrow and deep ditches or trenches are encountered, the flexing of the truck sectinswillnot serve any advantageous purpose and vit is preferable to lock l them so that the truck frames become rigid.

This can be done by various means, one such being shown as comprising a hook-shaped lug 40 on the joint of each truck frame and a pendent hook-shaped pawl 41 to cooperate therewith, said pawl being pivoted to the :recenti i mainframe and operated by means of a lever l2 adjacent to the drivers seat. pposite pawls .can be connected together. by means of a shaft 43 so that a single lever` will serve to operate both. These pawls normally will he out of engagement with their lugs and' the truck sections Aat such times are free' to ieX.` However, when conditions warrant thevpawlsl oder a ready means of locking the truck sections against downward movement at their joints.

'llie springs 25, on the rear truck sections, (cushion the shocks,- due to the vsudden upward movement of the said sections, and the spring mountings for the shaft 16 cushion` lthe shocks which occur when the iront end oi2 the machine strikes the ground aiter passover a sharp rise. Each truck, in so 'Ear as its flexing is concerned, is independent of the other and, therefore, is :tree to conform to conditions of ground which may be Wholly dissimilar tov the conditions of the ground over which the opposite truck is passino.

v1While articulated and rocking truck members have been employed before iii tractors of tlieseliplaying .track type, as shown and described in Patent No. 1,184,705 to Emil il.. Norelius dated May 23rd, 1916, yet the Eexing of the truck members was more or less limited andnot intended to lit an siiclijextreme conditions as the present -evice will operate under.

i Various changes iii the construction and arrangement of the vseveral parte herein shown and described may be made without departingfrom the spirit of my inventori as disclosed in the appended claims. lrnns "for instance in Fig. dan alternative structure is illustrated in which the rear truclr section l.- is pivoted at 21a similarly to the 'pivot construction 16 of the forward triicl section 13, previously described. The allowse'ctioiis is providedl by means of a bracket l0a and link 10"; the li-nk 1()b providing for the necessary straightening and'oendmg of 'the sections.' e

` lt is manifest that the method ofmoiuiting and articulating the truck sections and arranging the frontv and rear sprockets so that they move toward and from each other in unison with the change in angiilarity of the truck sections that the track belt is maintained at all times in operative position without danger of the track belt climbing the sprockets-on leaving the truck sections no' matter what pitcli-theitruclt sections ossume. Having thus described my invention, what l claim and desire to secure by Letters 1lzatent isl.. "in vehicle, a main frame, articulated roller truck mechanism for supporting 'the same, a seit-laying track upon which the one section by 'variations ance for articiilationbetween the two truck i roller truck mechanism operates, and fixed connections .between the truck mechanism and the mainframe permitting vertical rocking movement of the articulated sections, whereby they may' assume diderent relative positionsY varying from a straight line to an upwardly diverging angle oi' approximately 135, whereby to conform to the contour of the ground over which they are passing. v

2. ln a vehicle, the combination of a main frame, an endless, self-layng track, a truck supported within the track and carryingv theI weightl of the main frame, said truck in- .cluding a plurality o'f separate sections, and

a fixed pivotal connection between each.

truck section and 'the main trame such that the sections may `rock freely a vertical plane to assume various rel. vive positions from astraight line to an ii'owardly diverging angle oi" approximately 135..

3. ln a vehicle, the combination with a frame, oif a pair of seltleying tracks adapted to support the weight of the frame, triiclrs interposed between tlieframe and the tracks, caen truck comprising; a plurality of separate sections, a fixed pivotal connection betweeueacli truck section and tile main trame permitting oscillating` movement ,in a

rvertical plane, and a hinged connection be-4 "frame intermediate its ends and Yfree to move n E h tta. t di* l [i l) v10-b l away irom t e a -.er a its Joint, wnei.J y

to permit the track to conform to depressions in the ground. n

5. ln a tractor or1 the seltlaying type, axmaiii frame, front and rear frame members 'for supporting the main frame, each frame member being fitted with rollers adapted 'for operation upon the ground stretch or" the track, a driving sprocket wheel at'the rear of main iframe upon which the chain track rides, a guide wheel for the frontend oi the track jour traclr naled upon the front end oi" the iront truck meiriber, anda lined pivotal connection between the front-truck frame member andthe main frame permitting upward movement oig the forward portion of the front truck tti-aine member toenA angle oi approximately @los with the plane of the rear truck 'frame member. i

6.. ln a Vtractor of the self-laying traclz truck iso type, a main frame, front and rear truck. frame members Jier supporting the main frame, each frame memberbeing fitted with rollers adapted for operation upon the lground stretch of the track, a driving sprocket wheel at the rear oic the main frame rupon which the chain track rides, 'a guide wheel ior'the iront end of the track journaled upon the front end of the iront truck member, said truck frame members being hinged together at their adiaccnt ends, and iXed pivotal connectons between each mea ber and the main frame permitting them to ieX downwardly at their adjacent ends to assume an angle ci approximately 135.

7. ln a tractor of the self-laying track type, a main trame, a sectional truck frame Jfor supporting the main frame, each truck l.frame being ttedwith rollers for operation upon the ground stretch of the track, and

A connections between each truck traine section andthe main framev permitting rocki ing' movementJ in a vertical plane such that the truck iframe sections may 'assume different angular relations varying from ,a

- straight line to an upwardly diverging angle i, hinged Connections .between the twov truck of approximately 135o in passing over de-v pressions in the ground.

8. ln'a vehicle,`t'he combination of a main frame and an endless, self-laying track mechanism comprising a two-part roller truck, a sprocket wheel thereon, a sprocket wheel on the main frame, a track riding over said sprocket wheels and supporting the truck, aa pivotal connection between the front truck 'member andthe main frame, a .pivotal and slidable connection between' the rear truck member andthe main Jframe, and

members, said connections being so arranged that both truckmembers will rock in a vertical plane about'their pivotal connection. 1 with the main frame.

9. In a vehicle, the combination ci a main frame and an endless, self-laying trackl mechanism comprising a two-part roller truck,a sprocket wheel thereon, a sprocket wheel on themainrame, a track riding over said sprocket wheelsA and supporting-the truck, a'pivotal connection between the front truck member and the main frame, a' pivotal .and slidable connection betweenthe rear i truck/member and the main frame, hinged connections between the two truck members, said connections being so arranged that both truck members willrock in a vertical plane about their pivotal connection with the main. frame, the pivotal and slidableconnection" for the rear truck memberbeing located near the rear end thereof, and sprin s carried by the main, frame and resting; etachably upon the front portion of thejrear truck member to absorb theshocks due to upward movement 0f the Jforward portion of the rear truck member.

l0.` ln a vehicle, thecoinbination ci a main frame and an endless, self-laying traclr Amechanism comprising' a two-part roller Y cushion the main frame. l

ll. ln a vehicle a main trame articulated V 7 I roller truck mechanism for supporting saine, an endless track upon which sais truck mechanism travels, and connections .between the opposite ends ci sale truck mechanism and the'main frame permitting .the latter to move freely in a vertical direction at its joint, whereby to conform 'tc the contour of the ground.

g l2.v lin a vehicle, a main frame, articulated roller truck mechanism 'for supporting the same, an endless track upon which said truck mechanism. travels, connections between said-truck mechanismand. the main frame permitting the latter to move freely in a vertical direction atv its joint, whereby to conform' to the contour ci the ground, and means Jfor locking said goint so that the truck mechanism becomes rigid..

13. vlin a vehicle,a main irame, a two-pa`rt l roller truck mechanism forv supporting the main. frame, an endlesaself-layinfg track upon which said truck mechanism. travels,

connections between the sectionsfo said truck mechanism land the main frame, whereby to permit said truck sections to .move 'downwardly away from the'v main -rame'fat their adjacent ends, and means on .the-mainI vframe engageable with the truck sections toretain the latter against downward movement. l l p 14, ln a vehicle, a main frame, a two-part "roller truck mechanism for supporting the main Jframe, Yan endless self-laying track upon which said truck mechanism travels, a

fixed pivotal lconnection between the front section of said roller truck mechanism-and the main frame, and connecting means between the reartruck section and the main frame for allowing Vertical Swinging move. ment thereof. Y-

15. ln a vehicle, a main frame, 'an' artieul'lated roller truck mechanism for support-V ing the same, an endless track upon which 4said truck Amechanism travels, means for llo pivoting the forward section. of said truck y mechanism tothe main frame-'to permit, it

'to swing in relation to a fixed axis, and. la.; my hand in the presence of two subscribing connection between the main frame andthe Witnesses, rear end of the rear section of the truck mechanism for permitting it to' swing in PLINY E' HOLT' 5 relation tothe malin frame and in relation. Witnesses: l

to the front section o f thetruck mechanism. J OHN H. HERRING,

n :testimony whereof I havehereunto set VGr. BALL. 

